Failing a cable then switching circuit off?

[sharpy1983]

Hi Guys,

recently passed my 2391 and testing power cables on the motorways and A Roads. Came across this scenario last week.

3 core SWA cable has had Cpc cut and only line and neutral terminated, but cable is glanded and connected to the MET at both ends and I am getting a r1 r2 continuity reading when I drop the cable. Zs reading is within spec for protective device also but cable fails line-earth and neutral - earth on insulation resistance (0.5MOhm and 0.75MOhm). I isolated and locked off the circuit as the regs state that IR is a minimum of 1 meg.

Just been informed that I should have left the circuit on as the Zs is ok.

Just trying to clear things up as I am new to testing and want to do the right thing.

cheers!

 

[telectrix]

sod the Zs. a IR reading that low needs investigating. you did the right thing.

 

[sharpy1983]

Thanks mate

 

[Clive P]

Hi,
I'm with Tel on that one, sounds like the cable has been damaged and the earth has been chopped out as it's probably in contact with L-N, can only get worse; good call stick by your guns.

Regards.

 

[sharpy1983]

Cheers Clive I was thinking that's why the CPC had been chopped.

 

[Marvo]

I agree with the comments above. Possible the cable has been damaged somewhere along its length. Completely isolate the cable and disconnect the armour from the galnds. Mega between the armour and a known good earth. If the ins reading is low then the cable is a write-off. Also if the cable is damaged the armour will be corroding which means your Zs won't be reliable.

 

[Guest55]

so you've killed the power to lighting on a motorway / dual carrigeway cos of a I.R reading in excess of 500,000 ohms and a Zs value that complies ??
how much of the highway is unlit ?
how long will it remain out ?
did you get approval from your superiors to shut down lighting ?

so when theres a multi car pile up in the dark and the highways agency launch an investigaton do you think your actions will stand up to technical scrutiny ?
i dont , best get it switched back on sharpish , if you've still got a job.

 

[sharpy1983]

Biff, it's not a lighting circuit, it's a single 5 lane gantry and a message sign. The cable has an IR reading lower than what the regs state as a pass and my name and signature goes on the condition report so I'm making sure I cover my arse.

My actions will stand up to BS7671 and that's the important thing.

Guessing that's why your name is biff?

 

[Guest55]

where does it say in bs7671 that circuits below 1 meg IR should be isolated ?

anyways , if you think you did right then thats all that matters , what do i know lol.

 

[Marvo]

Lol, you didn't say exactly what the cable supplied but gantry signage and even street lighting is just a 'nice to have' we do just fine without them where I am

Maybe just report it for further investigation or replacement.

 

[MDJ]

Lol, you didn't say exactly what the cable supplied but gantry signage and even street lighting is just a 'nice to have' we do just fine without them where I am

Maybe just report it for further investigation or replacement.

You have guns there don't you fella so street lights are not a requirement haha, okay sorry Just kidding.

 

[sharpy1983]

Doesn't say it has to be isolated but it does say that minimum IR for a LV circuit is 1MOhm. Plus this cable was PIRd 5 years ago and the observations stated the cpc had been cut, for what reason other than a short between line and cpc?

Nackered Cables direct buried on sides of wet motorways won't last long and I'm not being the go to guy when a contractor or joe public gets a belt.

you might be a bit of mr know it all I'm just being safe.

 

[sharpy1983]

What does it matter what's on the end of the cable? It's street furniture, it's in the regs, it's failed!!!

 

[Des 56]

I am not commenting on the justification of your actions with regard Bs 7671 because that's your opinion and you are the guy on the job

What I would like to know
You are testing the installation and will be signing the report that goes along with that testing.what authority do you have for deciding to isolate this circuit?
I would have thought,permission to do so would have to be sought before this action is taken
I can well understand something that is an immediate danger not being re energised by yourself,but this is a system degradation that needs attention rather than something needing immediately isolation

 

[SparkyJoe]

so you've killed the power to lighting on a motorway / dual carrigeway cos of a I.R reading in excess of 500,000 ohms and a Zs value that complies ??
how much of the highway is unlit ?
how long will it remain out ?
did you get approval from your superiors to shut down lighting ?

so when theres a multi car pile up in the dark and the highways agency launch an investigaton do you think your actions will stand up to technical scrutiny ?
i dont , best get it switched back on sharpish , if you've still got a job.

Dunno about yours, but my car has lights.

 

[sharpy1983]

Hi Des, that's why I've asked the question on this thread,

I suppose that seeing the cpc cut and the failure of IR between both live conductors and earth caused me concern but I can see that it is a degraded cable which will be put in for a replacement.

the general consensus is that, if the Zs complies, then the circuit should remain live but should be noted in the observations that the cable requires replacing due to the IR failure.

What code would you enter in the obs part of the report? C1,c2,or c3?

 

[polo1]

Inspectors carrying out an EICR do not have implied authority to isolate any (even deemed dangerous) circuits on their own authority. What you should do is contact the owner for permission to isolate a circuit that you deem to be an immediate danger and issue a danger notice. If the owner agrees, no problem, isolate. If they don't you have the Danger Notice to cover your ar**.

Regards.

 

[44ALLAN]

Sharpy...............read posts 2/4/6 and 15 again and digest mate.

 

[BrianDB9]

Its always a difficult call to isolate.

I think it needs bringing to the attention of the employer to define what action they would like you to take when you find such situations , if they do a risk assessment and judge such a situation as more of a potential danger to traffic than other maintenance staff then they will have to answer for the consequences but you will have the employers instructions in writing and that would be your get out of jail free card.

 

[sharpy1983]

Thanks Allan

 

[sharpy1983]

Brian, I've done exactly that today, emailed my gaffer requesting confirmation from the customer and company in similar circumstances. New to testing and enjoying it but just don't want to get caught out but on the other hand don't want to be disconnecting circuits which are failing if the customer wants them left energised. Bit of a grey area I suppose. I thought the competent person would be able to make the decision to knock off a failed circuit if it does not comply with the regulations. Suppose this scenario is like taking ur car for an mot and the tyres have no tread, they still drive but not within spec!! Can you carry on driving or does ur car fail its mot? Fail, car doesn't go back out, what's the difference?

 

[sharpy1983]

Thanks polo

 

[trev]

Sharpy I'm guessing you had to tell someone that you isolated this bit of kit, and I'm also guessing that because you're here asking about it you haven't had your balls handed to you on a plate. If both of the above are correct then there's no sweat mate, like one of the guys said most cars have lights these days. OK there could be traffic conditions up ahead that they need to know about but if it's a case of causing a jam or a verge worker frying I know which I'd find easier to live with. The cable can be re energised if someone over rules you, it's a bit more difficult restarting someone's heart I think.

 

[sharpy1983]

Exactly Trev,
I'd informed the chain of people who I had to inform on the day, isolated the circuit and informed them if the situation and the readings.

 

[sharpy1983]

Used the word inform too much then!!!

 

[trev]

I was grateful to be informed of the information your informative post contained I believe informing the information to all those who should be informed of it exonerates you of any blame

 

[sharpy1983]

Thank you Trev, you have been very informative this evening!!! Cheers again mate

 

[44ALLAN]

Yes Prime Minister

 

[polo1]

Sharpy1983, I was re-reading my earlier post in the cold light of day and think it may have come across a bit "holier than thou" - absolutely not my intention , but that's emails for you! Being prepared to ask for opinions and accept/reject the opinions given as you see fit is exactly the right approach.

As a spark who takes my role seriously, particularly where I believe there is potential danger to users/third parties from an installation, I would welcome the power in law to isolate a circuit or installation in such a condition. Why? 'Cos I've seen many, particularly retail, installations where the owner's only interest is their bottom line and getting them to make essential improvements is well nigh impossible. This facility exists in gas, why not electricity?

I've learned the hard way the limits of a spark's ability to take "sensible" action in the face of danger to users and have just had to bite the bullit and issue a danger notice. For the type of work you are involved in, your employer could seek the agreement of the customer's electrical duty holder to be allowed to isolate and inform any imminently dangerous situations you come across - the best of both worlds imho.

Regards.

 

[sharpy1983]

Thanks for the reply polo, appreciate the advice ill be straight in the office on Monday ensuring we have clarification on what actions I can and cann

- - - Updated - - -

Cannot take when coming across similar scenarios. Thanks again mate

 

[snowhead]

This facility exists in gas, why not electricity?

Unfortunately it doesn't.
I'm also Gassafe reg.

Gas regs state "With the permission of the responsible Person, isolate the appliance"
If the R.P says catagorically no, you cannot isolate, the next move is to contact National Grid Gas, who do have the legal power to isolate.

However isolation can be stopped if there is an overriding safety factor like a complex chemical production process then failing and causing a greater danger of explosion than a gas leak would.
A few thousand loaves not getting baked would fit that clause.

 

[Spark1979]

Surely you've covered yourself if you right it on the report and sign it. Personally as far as I am concerned you have no power to disconnect anything even though we'd love to. Image every report done if we disconnected everything not to the regs or dangerous people and shops would have no lights and sockets everywhere.

 

[sharpy1983]

Cheers for the advice Darren, I'm off to the office first thing to discuss it so ill let you know the outcome

 

[trev]

Surely you've covered yourself if you right it on the report and sign it. Personally as far as I am concerned you have no power to disconnect anything even though we'd love to. Image every report done if we disconnected everything not to the regs or dangerous people and shops would have no lights and sockets everywhere.

There's a massive difference between not complying with current regs and dangerous mate

 

[Spark1979]

I hear what your saying Trev but all we can do is advise, I had a fault on some sockets in a factory unit, no ring continuity high cpc readings at sockets told the manager there still using them, there would be hell on if I turned them off. You can only do what your paid to do, and that's test and report.

 

[markythesparky]

id agree sharpy, Your were employed to report on the condition of the installation and you have found a CPC that could well be live. i think i would haev done the same thing. the point is that you then report the fault to the owner or engineer and they deicd what to do. if they take months deciding then that their problem not yours. if you had left it and someone had been hurt your bosses would have been quicker than an apprentice with an exam to run away from it and pass the blame. the way you have left it is that its in their court.

You have made it safer than it was! i presume you have listed your actions in the report to cover yourself (just in case some idiot goes and turns it on again)?

 

[ian.settle1]

Sounds like there is a fault in a joint underground and rather than find it somone has cut the cpc at each end.

 

[sharpy1983]

Hello fellas, I noted it as a c1 on the eicr and made the customer aware that the circuit is off and will remain locked off until they give us further instruction. Still awaiting their decision.

 

[markythesparky]

Dont hold your breath.